It is well established that the regulation of transcription in eukaryotes is achieved by a strategy known as combinatorial control. Only exceptionally have the mechanisms been established by which the combined activities of multiple transcription factors result in the expression of specific sets of target genes. The present proposal aims at understanding the mechanism by which the C1/R complex is able to activate the genes of the anthocyanin biosynthetic pathway in maize. Based on our extensive preliminary results, a mechanism involving additional R-interacting factors is being proposed. The specific objectives of this proposal are aimed at I) characterizing the C1/R complex biochemically and II) characterizing molecularly already identified members of the C1/R complex to determine how they contribute to the R regulatory function. The dissection of this transcriptional complex will undoubtedly contribute to the general understanding of combinatorial gene regulation and on how transcription is regulated in all eukaryotes as many of the factors involved share proteins with similar domains in other systems including animals. The dispensable nature of anthocyanins and their conspicuous pigmentation provide advantages rarely found in other systems.